EC 3.4.21.95

Accepted name: snake venom factor V activator

Reaction: Fully activates human clotting factor V by a single cleavage at the Trp-Tyr-Leu-Arg1545Ser-Asn-Asn-Gly bond. Cattle, but not rabbit, factor V is cleaved, and no other proteins of the clotting system are attacked. Esterase activity is observed on Bz-Arg-OEt and Tos-Arg-OMe, and amidase activity on Phe-pipecolyl-Arg-NHPhNO2

Comment: Known from venom of Vipera russelli. Inhibited by di-isopropyl fluorophosphate, unlike the metallopeptidase russellysin (EC 3.4.24.58) that is specific for factor X [1]. In peptidase family S1 (trypsin family) [2]